The present invention relates to a composition comprising carbon nanofibers functionalized with at least one moiety, and more particularly, to a composition and method for making functionalized carbon nanofibers and nanocomposites.
Nanostructures have attracted much attention due to their unique properties for numerous applications such as polymer nanocomposites, electronic devices, field emission display, and hydrogen storage. Carbon-based nanostructures in particular, have shown useful mechanical, electrical, thermal and thermal-mechanical properties and also find application in many technologies, such as tires, chip packaging, epoxies, composites, radiators, heat exchangers, and shields for electromagnetic interference.
There are many types of carbon-based nanostructures, including, for example, buckeyballs, three-dimensional structures, two-dimensional structures, and one-dimensional structures. Traditionally, one-dimensional carbon-based nanostructures are divided into three categories based on their diameter dimensions: (i) single-wall carbon nanotubes or SWNT (e.g., 0.7-3 nm); (ii) multi-wall carbon nanotubes or MWNT (e.g., 2-20 nm); and (iii) carbon nanofibers or CNFs (e.g., 30 nm and above). Compared to SWNT or MWNT, CNFs are more attractive for their relatively low cost and availability in larger quantities as the result of their more advanced stage in commercial production. For example, vapor growth is a typical method for CNF production. With aspect ratios (length/diameter) commonly greater than 800, CNFs can be useful as nanolevel reinforcement for polymeric matrices. Furthermore, since their inherent electrical and thermal transport properties are also typically excellent, they can be used for tailoring their polymer matrix composites into affordable, lightweight, and multifunctional materials.
Some nanostructures can be difficult to process due to their insolubility in most common solvents. Noncovalent and covalent surface modification of nanostructures are two typical approaches to improve solubility in common solvents and dispersion in polymer matrices. While there are some reports of functionalization of SWNT to improve solubility in organic solvents or aqueous media as well as to optimize nanoscale dispersion and interfacial adhesion in solid matrices, there are relatively few reports concerning the covalent modification of CNFs.
Accordingly, there is still a need in the art for a method of functionalizing carbon nanofibers for use in polymer nanocomposites and other applications.